ESP8266 on batteries for years – part 5 – Cron Blog – My personal findings
ESP8266 Wireless Dev System - Non-Battery Version from BurgessWorld Custom Electronics on Tindie
DSTIKE Deauther MINI ESP8266 WIFI Development Board OLED NodeMCU with 2dB Antenna Battery Connector|Instrument Parts & Accessories| - AliExpress
Can i power this 'nodemcu esp8266 v3' using 7.4v or 8v power source in its microusb. actually i have two li-ion battery(3.7v) so , i am going to connect this battery in